Practitioners in the field of dentistry have long sought polymerizable compositions which would adhere well to dentin (and to tooth structure in general), and some commercially available polymerizable compositions have been utilized as dentin adhesives.
For example, there has been introduced in Japan a dental liner composition, under the name "Clearfil Bond System F" (hereinafter, "Clearfil"), utilizing a two-part resin system. The first (catalyst) portion of such resin system contains a polymerizable phosphoric acid of unreported structure, but believed to be ##STR1## and about 2 weight percent benzoyl peroxide. The second (accelerator) part of such resin system contains an ethanolic solution containing about 3 weight percent sodium benzene sulfinate and about 1 weight percent N,N-dihydroxyethyl-p-toluidine (the latter compound will be referred to hereafter as "DHPT").
My copending U.S. patent application Ser. No. 234,560, filed Feb. 13, 1981, now U.S. Pat. No. 4,482,505 describes polymerizable compositions which adhere well to dentin and enamel. These compositions contain an organic ester of one or more acids of phosphorus, said ester having chlorine or bromine bonded directly to phosphorus, and the organic radical of said ester containing at least one polymerizable functional group.
R. L. Bowen has described another means for obtaining adhesion to dentin, through the use of a multiple step procedure. In a first step of such procedure, a "mordant" prewash solution containing a cation having greater electronegativity than calcium (e.g., Fe.sup.+3, Cu.sup.+2, Al.sup.+3, Zn.sup.+2, or Co.sup.+2) is applied to a treatment site of a tooth. In a second step, a "polyfunctional surface-active comonomer", or "polySAC", is applied to the prewash-treated tooth surface. Next, a dental resin or composite material is applied to the polySAC-treated tooth surface and allowed to harden, see U.S. Pat. No. 4,251,565, Bowen, R. L., "Adhesive Bonding of Various Materials to Hard Tooth Tissues. VII. Metal Salts as Mordants for Coupling Agents", Dental Adhesive Materials, Proceedings from a Symposium held Nov. 8-9, 1973, Moskowitz, H. D., Ward, G. T., and Woolridge, E. D., Eds., pp. 205-221 (1974), Bowen, R. L., "Adhesive Bonding of Various Materials to Hard Tooth Tissues. XIV. Enamel Mordant Selection Assisted by ESCA (XPS)", J. Dent. Res., 57, 4, 551-556 (1978), and Bowen, R. L., McClendon, L. T., and Gills, T. E., "Adhesive Bonding of Various Materials to Hard Tooth Tissues. XV. Neutron Activation Analysis of Dentin Sorption of Mordant Salts", J. Dent. Res., 57, 2, 255-260 (1978). Additional information concerning the effect of mordant solutions (using ferric chloride as the mordant species) is contained in Jedrychowski, J. R., Caputo, A. A. and Prola, J., "Influence of a Ferric Chloride Mordant Solution on Resin-dentin Retention", J. Dent. Res., 60, 2, 134-138 (1981).